Toy building block



FIG. 1 is a top view of the toy building block;

FIG. 2 is a side view of the toy building block;

FIG. 3 is an end view of the toy building block;

FIG. 4 is an underside view of the toy building block;

FIG. 5 is a top perspective view of the toy building block; and,

FIG. 6 is an underside perspective view of the toy building block. 

The ornamental design for a toy building block, as shown and described. 